Sulphonation of coal tab distillates



Patented Jan. 7, 1941 SULPHONA'HON OF COAL TAB DISTILLATES Robert L Brandt and John m, New York, N. Y., assignors to Colgate-Palmollve-Peet Company, Jersey City, N. 1., a corporation of Delaware No Drawing. Application July i, 1938,

, Serial No. 218,018

Claims.

Thisinvention relates to a new process of preparing detergent compositions and to the method of their preparation. These improved composi-* tions may be generally described as the salts of 5 the products of the action of sulphonating agents upon coal tar distillates, manufactured in such a manner that the reactions are readily controlled, as set out in greater detail hereinafter.

The chemical constitution of coal tars while i) not completely known is known to vary with types and sources of coal and with the methods employed in manufacturing the tars, and these are recognized as being composed of mixtures of a great number of individual compounds of comparatively simple to complex structure. These compounds are generally aromatic in nature, usually alkylated and arylated aromatic compounds being present in large quantities.

Ordinarily, when coal tar oils or fractions 20 thereof are treated with sulphuric acid. P lymerization, oxidation, condensation and other types of reactions, as well as sulphonation and sulphation, occur in greateror less degree, depending upon, among other things, the strength of the acid, kind of oils, temperature, time of reaction, oil-acid volume relations, effectiveness of contact, etc. In many instances and in many ways, prior to this invention, coal tar oils and sulphonating agents, particularly sulphuric acid, have been re- 30 acted together and the products neutralized to produce wetting agents, but insofar as we have been able to determine, none of these products have been satisfactory as deterging, wetting, emulsifying, foaming and the like agents. Fur- 35 thermore, no method has been published, so far as we have been able to ascertain, which eifects a control or elimination of some or all of the unwanted reactions in attempts to produce wetting agents, detergents, etc., from coal tar oils; 40 hence by-products have resulted in these reactions which give'the final material undesirable odor and color and reduce the efficiency of the detergent. These by-products may produce a yellow stain or color in goods washed in solutions 45 of the sulphonated coal tars, may cause stickiness in hand washing, or may impart other undesirable properties to the final material.

Having in mind the defects of the prior art methods and products, it is an object of our in- 52 vention to provide a process of producing deterglng, wetting, emulsifying, foaming and the like agents from coal tar distillates superior to those heretofore known. 7

It is another object of our invention to provide 5 a process of controlling the reaction between coal tar distillates and sulplionating agents. A further object is to. provide a process of manufacturing deterging, etc. agents from coal tar distillates which is readily adaptable to commercial and industrial operation. A still further object 5 is to provide a continuous process of carrying out these reactions. Further objects will become apparent as the disclosures proceed.

- The foregoing objects and others ancillary thereto, we prefer to accomplish as follows: 10

According to the present invention we have discovered that coal tar distillates, which arepreferably prepared by distillation with the aid of steam and diminished pressure, such distillates generally boiling within the range of from about 200 to about 450 C. at atmospheric pressure, may be treated with a sulphonating agent in a liquid'sulphu'r dioxide solution, in such manner as to produce highly satisfactory and eflicient deterging, wetting, emulsifying, foaming and the like agents without at the same time forming any appreciable proportion of undesirable side reac-' 'tion products which detract from the value of the final product. In fact, the product appears to be of a generally difierent nature than those formed by other processes and much more effective for the intended purposes.

The coal tar oils for use according to this invention may be obtained from any of the usual types of coal, i. e., hard (anthracite) soft (bituminous), and brown (lignite) these terms are not intended to be limiting but to include all types of coals. A semi-hard (bituminous-anthracite) or a softer coal such as'bituminous, or brown (lignite) coal is to be preferred to the very hardest of coals as a starting material. The desired oils may be obtained by high or low temperature distillation, hydrogenation, or Berginization of coals, or by other equivalent or similar processes; and may be the products of liquefaction of coal, lignite, peat, etc, 40 and their distillation or conversion products of destructive distillation, hydrogenation. destructive hydrogenation and like processes. Coke oven and low temperature tars are excellent for our purposes. may be obtained and which find utility in our invention are those formed in the Blau and Pintsch processes. tween distillates derived from the above sources in the enumerated and similar processes and the oils and distlllates from shale oils, the latter are also contemplated as coming within the spirit of this invention.

The tar or oil is treated successively with caustic soda and sulphuric acid to remove phenol and Other tars from which distillates 15 I In view of-the simil it nitrogeneous bases and fractionated to yield distillates boiling within the desired temperature range. This caustic and acid treatment may take place either before or after fractionation. The resulting distilled oil may be used directly for sulphonation. It is often found desirable, however, to effect further narrowing of the boiling range of the coal tar oils by. redistillation or solvent extraction so as to yield fractions boiling between the desired limits.

The next step after obtaining the desired coal tar oil or extract or fraction thereof consists in dissolving such oil in liquid sulphur dioxide. Usually the 011 should be dissolved in approximately one-half to two times its volume of liquid sulphur dioxide. The resulting solution of oil in liquid sulphur dioxide is, even at low temperatures (below C.), very fluid and non-viscous.

Having the desired solution of coal tar oil in liquid sulphur dioxide, the solution is cooled to a temperature of about -15 to 20 C. and mixed with a sulphonating agent, such as strong fuming sulphuric acid, preferably also dissolved in liquid sulphur dioxide and at -l to --20 C. The temperature is kept below +5 C. during the initial mixing and preferably below -5 C. Agitation should be used and the process may be performed in a continuous or batch method. In the event a batch method is employed, it has been found preferable to add the acid to the oil instead of the reverse, since this permits closer tem perature control.

The quantity of acid used and its strength will depend on the type of hydrocarbon fraction, the reaction temperature, liquid sulphur dioxide dilution and the characteristics desired in the finished products. Fuming sulphuric acid (commercial 20% oleum) in a quantity about equal in weight to the material to be treated and dis-. solved in liquid sulphur dioxide has been found satisfactory. Sulphur trioxide, chlorsulphonic acid or other sulphonating agent soluble in liquid sulphur dioxide may also be used. By dissolving the sulphonating agent in liquid sulphur dioxide, it is possible to add this agent to the liquid sulphur dioxide solution of the coal tar distillate over a much shorter period of time without excessive temperature increase such as would result if the sulphonating agent were added directly to the coal tar oil solution. Furthermore, this procedure enables one to take full advantage of the rapid reaction rates, and in addition the physical properties of the mixture (low viscosity) permit rapid dissipation and removal of the heat of reaction. Because of these conditions, the method makes it possible to maintain high thruput rates. The reaction is carried out at low temperatures which prevent or minimize oxidation, polymerization and other undesired reactions that always occur at the usual sulphonation temperatures.

After the initial heat of reaction has substantially been dissipated, the reacting mixture will be raised to a temperature of about +5 C. by control of cooling. Generally, mixing of the acid and oil solutions will be accomplished in a few minutes, usually less than one minute. The reaction will be permitted to continue for a period usually not greater than fifteen minutes from the initial mixing of the reactants and preferably no longer than five minutes.

Treatment with the sulphonating agent having been completed, the reaction mixture is diluted with cold water to stop further action of the sulphonating agent. After water dilution, the

next step is to separate any unreacted hydrocarbons from the mixture. Several alternatives are possible. One is to hold the liquid sulphur dioxide solution of sulphonation products and acid under pressure and add enough water to separate a liquid sulphur dioxide phase. This layer, consisting of the bulk of liquid sulphur dioxide containing most of the unreacted hydrocarbon oil in solution, may be directly removed. The aqueous solution of the sulphonic-sulphuric acids may be further extracted with fresh liquid sulphur dioxide. After removal of the residual dissolved sulphur dioxide from the aqueous layer by evaporation, the solution may then be neutralized with a basic compound such as caustic soda, soda ash, ammonia, lime, triethanolamine, or the like.

Alternatively, to prepare a finished high quality product, the solution, after separating the sulphur dioxide, may be washed either before or after neutralization with a low boiling hydrocarbon solvent. Gasoline, such as Pennsylvania grade, that is substantially entirely volatile in the presence of steam at a temperature below that at which the final product is to be dried, is very satisfactory for this purpose, since it readily dissolves any residual unsulphonated oil and some or all of the undesired products, and any of the gasoline that remains in aqueous solution is completely removed itself in the drying operation.

It has been discovered that, if the washing is performed after dilution with water but before neutralization, certain dimculties due to the formation of emulsions are avoided and, for that reason, the step is best performed at that time.

The water solution of the reaction product may or may not be boiled before solvent extraction a'nd'neutralization to destroy any unstable sulphates present. After neutralization, the solution may be boiled in an excess of caustic soda, or the acid solution may be run into a calculated amount of hot concentrated caustic soda to decompose unstable compounds. The solutions of neutralized sulphuric acid reaction product, which may also contain a considerable proportion of the sulphate of the neutralizing material as a result of its reaction with the excess sulphuric acid present, may be used in this state for many purposes, or the accompanying inorganic salt may be removed by extracting the active ingredient with isopropyl, butyl or with substantially water-insoluble alcohol in which the active ingredient is soluble, to free it from the by-product sulphate formed in the neutralizing process, or

done, for example, byadding to the sulphonated mixture a slurry of hydrated lime in excess of the amount suflicient to complete the neutralization. Water-insoluble calcium sulphate will be formed by sulphuric .acid. The calcium salt of the detergent being water soluble, the mixture may be filtered to remove the calcium sulphate. The filtrate containing the calcium salt may then be evaporated and the salt obtained in dry or concentrated form.

If salts otherthan the calcium salt are desired, the calcium salt solution may be treated with a solution of a suitable calcium precipitant, as, for instance, sodium carbonate, sodium oxalate, or sodium phosphate, in an amount slightly in excess of that required to replace all of the calcium in the detergent with sodium and so precipiate the calcium as the'carbonate, oxalate, or phosphate. After this precipitate is filtered oil, the solution is ready for concentration.

In some instances it may be desirable to prepare corresponding ammonium, ethanolamine, magnesium, potassium, or other salts. These may be formed in the same manner as the sodium salts, that is, by substituting the corresponding ammonium, triethanolamine, magnesium, potassium, or other salts, for the sodium carbonate, oxalate, or phosphate mentioned above, or by replacing the desired basic ion. Alternatively, ammonia or triethanolamine may be added, together with carbon dioxideto precipitate the calcium.

The salt-free product may be used alone or in any of the compositions and combinations referred to elsewhere in this specification. A desirable product may be obtained by incorporating with the salt-free detergent the desired amount of an alkaline material such as sodium carbonate to make an efiiclent washing and cleaning material.

The final material, etiher with or without the byproduct sulphate, may be formed into beads, flakes, chips, powders, solutions, liquid or plastic emulsions or other forms into which soap or other detergent or emulsifying materials are ordinarily made, either with or without the ingredients commonly used in such combinations, for example, active or inert soap fillers, water softeners, perfumes, abrasives, soap and other detergents, fats, oils, waxes, and gylcerine. The sulphonate product can be incorporated with the usual fatty acid soaps and the composition formed into bars, flakes or powders. This combination yields an inexpensive detergent composition possessing all the desirable properties of the ordinary soaps and the additional advantages of operativeness in hard and sea water and of increased wetting, emulsifying and deterging eificiency.

A more detailed understanding of the principles of this invention may be achieved by a consideration of the following specific examples of the process of making-the improved compositions.

Example 1 v A crude distillate obtained from a tar produced by the low temperature carbonization of West Pennsylvania bituminous coal in a vertical retort was purified by extracting with caustic alkali and then with 5% sulphuric acid, and thereafter redistilled so as to yield a fraction boiling between 120 and 150 C. at 5 mm. pressure. One volume of the coal tar oil fraction was mixed with half its volume of liquid sulphur dioxide and cooled to -15 C. Commercial oleum equal in weight to the coal tar oil fraction, was dissolved in a volume of liquid sulphur dioxide equal to that used to dissolve the oil cooled to -15 C., and added to the solution .with agitation. Mixing the two solutions required less than a minute. The operation was performed under pressure in a jacketed autoclave provided with a stirring device, thermometer and pressure gauge. Temperature control was maintained by circulating a cooling fluid through the jacket of the autoclave and the temperature was at no time permitted to rise above 5 C. during the mixing of the solution. After the acid solution addition, the'temperature was raised to +5 C. and maintained at that point for about three minutes, agitation being continued. At the end of this time the mixture was immediately diluted with twice its volume of ice water.

tially volatile below 250 F.

After dilution with water the liquid sulphur dioxide was removed by evaporation and the aqueous layer then heated to 45 C. to removeany residual sulphur dioxide. The aqueous solution was then batch-washed several times with 20% of its volume of gasoline (end boiling 250 F). The aqueous solution of sulphuric-sulphonic acids mixture was neutralized by pouring into a calcu lated quantity of very strong caustic soda and brought to a boil. The neutralized solution was then taken to dryness on the soap-drying rolls at a,roll temperature of 250 F.

The above operations yielded a substantially dry, flufiy powder just off-white in color, having no odor in the dry state. Aqueous solutions, when rubbed into a lather on the hands, gave no odor. Dilute solutions of varying concentration were excellent foamers (comparing favorably with soap), excellent washing materials and also powerful wetting-out and emulsifying agents.

Example 2 A coal tar oil fraction somewhat heavier than that used in Example 1 was obtained from the same source and purified in the same manner. This fraction boiled between 150 and 170 C. at 5 mm. pressure. One volume of this coal tar oil was dissolved in approximately an equal volume of liquid sulphur dioxide and the solution was cooled to around 20 C. An amount of 20% oleum about equal in weight to that of the oil to be sulphonated, dissolved in liquid sulphur dioxide of about half the volume used for dissolving the coal tar oil fraction, was cooled to -20 C. and added to the sulphur dioxide solution of oil over a period of about one minute. The above operation was carried out in a jacketed autoclave provided with a stirring device, thermometer and pressure gauge. Temperature control was maintained by circulating a cooling fluid through the jacket. The temperature during mixing was not permitted to rise above +5 C., and it was maintained at that point for about ten minutes. At the endof this period, ice-water was added and the sulphur dioxide separated as a vapor by releasing the pressure at a temperature below +10 C.

The aqueous solution or dispersion was.imme diately batch-washed several times with 20% of its volume of gasoline, all of which was substan- It was then neutralized with caustic soda.

Etrample 3 A crude distillate obtained from a tar produced by the low temperature carbonization of a West Pennsylvania bituminous coal ina verticalformed in a jacketed autoclave provided with a stirring device, thermometer and pressure gauge. Temperature control was maintained by circulating a cooling fluid through the jacket of the autoclave and at no time was the temperature permitted to rise above -5 C. during the mixing. The temperature was raised to +5" C. and

maintained at that point for about three minutes, agitation being continued. At the end of this period the material was diluted with twice its volume of ice water, and the sulphur dioxide permitted to evaporate. The unsulphonated hydrocarbon oil was extracted from the mixture with ethyl ether and the remaining aqueous solution was neutralized with caustic soda taking .care to adjust the final pH to a value of 5 to '7. This mixture was then dried on soap drying rolls. The product was a light colored powder having a slight yellow tinge. It readily dissolved in water and gave a solution that was almost colorless and entirely without odor. 70% of the oil was sulphonated by this procedure, giving a total weight of final product, including the salts formed in the neutralization, of 139 grams, when grams of oil were used as starting material. Of this 139 grams, 71.95% was active ingredient and the remainder inorganic salts. A V solution of the material in soft water gave 300 cc. of foam and a 1% solution gave 400 cc. of foam. In hard water (250 p. p. m.) a solution gave 200 cc. of foam.

Example 4 A somewhat heavier fraction of an oil, obtained in the same way as that of Example 3, was sulphonated in the same manner and a very similar product was obtained. This fraction boiled between and 170 C. at 5 mm. pressure. Using 100 grams of oil as a starting material, 67% of the oil was sulphonated, yielding grams of product of which 63.71% was active ingredient. A solution yielded 310 cc. of foam in soft water and a 1% solution, 410 cc. of foam. In hard water (250 p. p. m.) a solution yielded 375 cc. of foam.

Oleum and chlorsulphonic acid have been disclosed in the above examples as the sulphonating agent; other common sulphonating agents such as sulphuric acid, sulphur trioxide, or sodium chlorsulphonate may be used. After the sul-' phonation the sulphonic acids may be neutralized either prior to or after separation from the other ingredients and the salt formed may be allowed to remain in the final product or be removed as desired. Caustic soda will ordinarily be used as the neutralizing agent but other neutralizing agents such as caustic potash, ammonia, the ethanolamines, andsoda ash may be used for this purpose. The final product may be dried by the use of a drying roll as described above or by spraying or any other known process. The final products may be in the form of powders, chips, beads, flakes, cakes or bars, solutions, creams, pastes, or any other form in which it may be desirable to utilize them.

As noted heretofore, these sulphonated coal tar distillates are very versatile and may be used in manufacturing and stabilizing aqueous dispersions of .water insoluble or nearly water insoluble substances such as mineral oils, vegetable oils, paraffin, asphalt, tar, sulphur, rubber, resins, hydrocarbons, higher alcohols, and other oxygen-containing compounds. Still other uses are in the flotation of ores and in the manufacture of cosmetics, such as cold cream, vanishing cream, cleansing creams and hand lotions. shaving creams, dental cream, dry baths, shampoos. In addition, they may advantageously be incorporated in paints, varnishes, lacquers, wood preservatives, salad oils and mayonnaise, ice cream, root beer, margarine, agricultural sprays, laxatives, coatings for paper and the like, floor,

leather, automobile, furniture and other types of polishes, inks, bituminous emulsions such as road binders, mold dressings, confections, dye emulsions, photographic emulsions, medicinal and pharmaceutical emulsions, and cutting and lubricating oils. Further, these agents may be used for emulsifying immiscible liquids for facilitating chemical reactions, such as aqueous ammonia and alkyl-halides for the production of alkylamines. They are especially useful in textile manufacturing and treating processes.

Although these particular sulphonation products have unusual dispersing properties, it may be desirable to use suitable additional agents such as soaps and/or soap flllers,'resinates, and other sulphated and sulphonated compounds. Other materials that may be incorporated include coloring matter such as dyes, lakes, and pigments; germicides and insecticides such as phenol mercury chloride, phenyl mercury nitrate, alkylated phenols and mercuric chloride; abrasives and inert fillers such as grit, silex, pumice, feldspar, precipitated chalk, infusorial earth, bentonite, talc, starch, air and/or gases; liquids including carbon tetrachloride, trichlorethylene, glycerine, alcohol, triethanolamine, carbitol, phenol, hexalin, pine oil, and naphtha; perfumes and deodorants; fats, oils, waxes, gums or resins; caustic soda, potash, and ammonia; and any of the common water soluble salts such as sodium carbonate, borate, silicate, phosphate, sulphate, chloride, acetate, bicarbonate, sesquicarbonate, hypochlorite, thiosulphate, hydrosulphite, hyposulphate and the water soluble meta, tetra, and pyrophosphates, or the corresponding ammonium, amine, and potassium salts thereof. The type of addition agent to be used, of course, will depend on the ultimate use of the new composition. It has also been found advantageous to admix vitamin containing materials or materials capable of forming vitamins with the products prepared in accordance with the present invention. Thus, materials such as sterols may be separately irradiated with radioactive rays such as ultra violet rays, Rtlntgen rays, infra red rays, and the like, and then added to the products described above during their preparation; or the sterols or other similar materials may be first incorporated in the present products, after which the mixtures are subjected to the desired radiation. Although it is possible to utilize to advantage many kindsv of vitamins in the manner referred to, theaddition of vitamins A, D and F has been found the most desirable, as these vitamins appear to be the best adapted for action on or through the skin, vitamin A exerting an anti-infectious action, vitamin D an anti-rachitic action, and vitamin F havinga generally beneficial effect insofar as the nourishment and health of the skin itself is concerned.

The term sulphonates is used herein to designate the product resulting from the action of sulphuric acid, oieum or other sulphonating agents on hydrocarbon oils, thus including compounds of the type R-SOaX and of the type R-OSOaX, where R is the organic radical and X is a base which forms a water-soluble salt of the whole sulphonate or sulphate. Furthermore, the details of the process, such as the quantities of the reagents, their concentrations, and the time periods and temperatures for the reactions are but examples of satisfactory constants for a particular type of coal tar distillate. As the type of coal tar distillate ls varied, as it may be within the scope of this invention, the several factors will necessarily vary, but the application oi the general principles set iorth herein, and the varying of these factors in accordance with the needs of the particular situation, are within the concept of this invention,

While we have disclosed only gasoline and ethyl ether for use in purifying or washing the aqueous solution of sulphonic acids by removing any unsulphonated hydrocarbons, other solvents such as dichlorethylene, ethylene dichloride, propylene dichloride, dichlor ethyl ether, monochlorbenzene. carbon tetrachloride and many others may be employed for the same purpose.

Where any one or more of the terms deterging, dispersing, washing, wetting, emulsifying, foaming, frothing, agents or textile assistants is used herein, the interpretation thereof is intended to include compounds having one or more oi the properties possessed by the named agents.

The process hereinbeiore disclosed as a batch method may be carried out continuously or intermittently in suitably arranged apparatus.

We claim:

1. A process of preparing detergents from coal" ing agent for a period not substantially in excess of 15 minutes at sub-atmospheric temperatures, arresting the reaction and neutralizing the reaction mass.

3. A process of preparing detergents from coal tar oil which comprises treating a coal tar oil fraction boiling within the range 200-450 C. in liquid sulphur dioxide solution with a sulphonating agent and completing the desired sulphonation at sub-atmospheric temperatures, arresting the reaction by adding to the reaction mixture a quantity cold water suiilcient to inhibit further reaction and neutralizing the reaction'mass.

4. A process of preparing detergents from coal tar oil which comprises treating a coal tar oil fraction boiling within the range 200-450" C. in liquid sulphur dioxide solution with a sulphonating agent for a period not substantially in excess of 15 minutes at sub-atmospheric temperatures, arresting the reaction by adding to the reaction mixture a quantity of cold water suilicient to inhibit iurther reaction and neutralizing the reaction mass.

5. A process of preparing detergents from coal tar oil which comprises treating a coal tar oil fraction boiling within the range 200-450 C. in liquid sulphur dioxide solution with a sulphonating agent for a period not substantially in excess of minutes at sub-atmospheric temperatures, arresting the reaction by adding to the reaction mixture a quantity of cold water sumcient to inhibit further reaction and neutralizing the reaction mass.

ROBERT L. BRANDT, JOmI ROSS. 

